Panerai began making watches in Florence, Italy back in 1860, but it wasn’t until the 1930s that the firm produced its first wristwatch. By then its roots in Florence were as deep as those in Switzerland, where Panerai watches were produced.
The breakthrough for the company was an order for diving watches from the Italian Navy, for whom Panerai had been creating instruments of various types since the turn of the century. With a war coming on, the navy was keen to outfit its elite corps of frogmen with wristwatches.
Featuring a Rolex movement, the limited-edition Panerai Radiomir (only 300 were made) was designed for use by commandos and torpedo riders—frogmen who rode a slow-moving torpedo toward a target before attaching a timed mine to the underside of a ship and then riding away. The watches had a cushion-shaped case, a screw-down crown to keep water out of the movement, and oiled-leather straps that were long enough to be worn on the outside of a diving suit. Given their limited supply and the tough conditions they were subjected to, these watches are very highly prized by collectors today.
The watch took its name, Radiomir, from the luminous material that Panerai first developed in 1910. Made of zinc sulphide and radium bromide, Radiomir allowed the numbers and hands on a watch to be read in dark conditions. It was replaced in 1949 by Luminor, which glows thanks to the presence of tritium, a less-dangerous compound than radium bromide.
Throughout the 1950s and ’60s, Panerai continued to produce wristwatches for the Italian Navy in regular and destro (left-handed) versions. Some watches from this period were known as Trittico watches, thanks to their trio of features, which included a depth gauge.
Panerai also made Kampfschwimmer watches, some with so-called California dials (numbers on the bottom, Roman numerals on the top), for Germany’s only postwar commando unit. And in 1956, Panerai created a large-face Radiomir watch for the Egyptian Navy.
Panerai might have remained a military diving watch in the minds of the public had it not been for Sylvester Stallone, who, in 1995, purchased a Luminor while on location in Italy. Sales of the watches jumped after its debut in Stallone’s “Daylight,” and Sly even had some watches—dubbed Slytech—made with his signature engraved on the back. These he gave as gifts to friends, including fellow action hero Arnold Schwarzenegger.